Which features are found in chordates, at least at some stage of their life history?
A. A neurogenic heart dorsal to the gut.
B. The pharynx is perforated by gill slits.
C. The central nervous system is ventral, solid and single.
D. A tail that extends beyond the anus (post-anal tail).
E. A flexible, rod-like notochord dorsal to the gut.
Choose the most appropriate answer from the options given below. 

B, D and E are the features of chordates. A and C are not features of chordates. 
A. In chordates, the heart is myogenic and ventral to the gut.
B. The pharynx of chordates is perforated by gill slits. These openings in the pharynx are used for filter-feeding or gas exchange.
C. The central nervous system of chordates is dorsal, hollow and single. Ventral and solid nerve cord is characteristically found in nonchordates.
D. Chordates typically possess a postanal tail, which is a tail that extends beyond the anus. 
E. All chordates possess a notochord, at least at some stage. The notochord is a flexible, rod-like structure that lies dorsal to the gut and ventral to the nerve cord. It provides support and rigidity to the body. In some chordates, the notochord persists throughout life; in others, it is replaced by the vertebral column (backbone).